Conveying installations using pneumatic tubes

ABSTRACT

The present invention deals with improvements to conveyor installations using pneumatic tubes. Said improvements comprise connecting the pneumatic tube element closed at one of its extremities is a dispatching-receiving station with the conduit of a pumping machine by means of two pipes each provided with a one-way floating clapper-valve, said valves being mounted in opposition, the pipe closer to the closed extremity of the pneumatic tube element permitting the passage of air only from the conduit of the pumping machine towards the pneumatic tube. This improvement is particularly simple, effective and reliable for conveyor installations provided with a single pneumatic tube connecting different dispatching-receiving stations.

nited States Patent [1 1 artin Dec. 11, 1973 CONVEYING INSTALLATIONSUSING PNEUMATIC TUBES [75] Inventor: Rene Jean Martin,

Villeneuve-La-Garenne, France [22] Filed: Apr. 17, 1972 [21] Appl. No.:244,655

[30] Foreign Application Priority Data June 30, 1971 France 7124015 [52]U.S. Cl. 243/19, 243/2 [51] Int. Cl. 865g 51/32 [58] Field of Search243/19, 1, 38, 13, 243/2; l37/533.17, 533.19

[56] References Cited UNITED STATES PATENTS 3,410,501 11/1968Thorburn.... 243/5 564,427 7/1896 Jacques 243/5 55,531 6/1866 Peabody137/533.l9 1,565,650 12/1925 Kee 137/533.17

1,609,924 12/1926 Witman l37/533.17 3,306,555 2/1967 Tonne 243/19FOREIGN PATENTS OR APPLICATIONS 1,192,981 5/1965 Germany 243/191,207,880 12/1965 Germany 243/19 Primary Examiner-Evon C. BlunkAssistant Examiner-James L. Rowland Attorney-Karl W. Flocks [57]ABSTRACT The present invention deals with improvements to conveyorinstallations using pneumatic tubes.

Said improvements comprise connecting the pneumatic tube element closedat one of its extremities is a dispatching-receiving station with theconduit of a pumping machine by means of two pipes each provided with aone-way floating clapper-valve, said valves being mounted in opposition,the pipe closer to the closed extremity of the pneumatic tube elementpermitting the passage of air only from the conduit of the pumpingmachine towards the pneumatic tube.

This improvement is particularly simple, effective and reliable forconveyor installations provided with a single pneumatic tube connectingdifferent dispatching-receiving stations.

2 Claims, 5 Drawing Figures CONVEYING INSTALLATIONS USING PNEUMATICTUBES The present invention relates to improvements in conveyorinstallations using pneumatic tubes, and especially those in which theconveyance ofpneumatic carriers is effected in a single pneumatic tube,either in one direction or in the other. These improvements concern thedevice for braking the pneumatic carriers, especially at the moment oftheir arrival at a station of the system which is capable not only ofreceiving but also of despatching carriers of this kind. I

The advantage of the pneumatic tube is that it conveys the documents orsamples which are entrusted to it as rapidly as possible. It istherefore essential to slow down the arrival of the carriers holdingthese documents or samples so as to prevent a violent shock liable tocause a considerable noise and abnormal wear of the equipment at thereceiving stations, and even damage to the carriers themselves andfragile objects carried by this means.

A known method of obtaining this braking, and which is simple andeffective, consists of causing the carriers to arrive in an element ofthe pneumatic tube which is closed at one of its extremities, so thatthe carrier, once propelled into this tube element compresses the airlocated between itself and the closed extremity of the pneumatic tube,which results in a slowing-down and stopping action on the conveyorcarrier.

This device gives complete satisfaction in pneumatic installations whichhave two tubes, an outgoing tube and a return tube, in which thepneumatic carriers always travel in the same direction.

This is not the case in installations with a single pneumatic tube,inside which the carriers can travel in one direction or the other,depending on whether a given station is operating as a dispatching or asa receiving station.

The invention consists of adapting the known braking device for carriersby pneumatic damping at the end of the travel to pneumatic installationscomprising a single tube in which the travel can be effected in bothdirections.

In installations of this kind, the slowing-down of the carriers in apneumatic tube element closed at one of its extremities, comprises,according to the invention, at each extremity of the said element, apiping system provided with a floating valve which allows the air topass in one direction and prevents its passage in the other, the twovalves being mounted in opposition in such manner as to permit theintake of air at the closed extremity of the element.

The two pipes are coupled to the conduit system of the pumping machinewhich can operate either on suction or on delivery and provides thepower necessary for the pneumatic displacement of the carriers.

During reception, the carrier may be either drawn or expelled into thepneumatic tube element closed at one of its extremities. In either case,the floating clappervalve located on the upstream side will be open andthe floating clapper-valve on the downstream side with respect to thedirection of movement of the carrier will be closed, which ensures theslowing down of the carrier when it reaches this element.

A device of this kind has the advantage of permitting fully automaticoperation, under the sole effect of the direction of the flow of airutilized for conveying the carriers.

The invention will now be illustrated by means of a certain number ofexamples of construction shown in the accompanying drawings, in which:

FIG. 1 shows a pneumatic station according to the invention providingfor both reception and despatch by a single tube;

FIG. 2 shows a pneumatic installation according to the invention, withtwo despatching-receiving stations and two machines which can work insuction;

FIG. 3 shows a pneumatic installation according to the invention, of thesame kind as that shown in FIG. 2, but permitting the operation in thesame direction of two pneumatic carriers at the same time, each locatedin a different circuit;

FIG. 4 represents another pneumatic installation according to theinvention, comprising a series of four despatching-receiving stationscoupled in parallel with a main pneumatic tube and working with apumping machine which alternatively creates either a vacuum or apressure;

FIG. 5 represents an alternative form of a pneumatic installationaccording to the invention, comprising a volumetric blower machine.

According to the example of construction shown in FIG. 1, adespatching-receiving station for pneumatic carriers according to theinvention, comprises a pneumatic tube element 1, serving for theconveyance of the carriers and having its extremity 2 closed by ashutter 3. This element 1 is connected by two pipes 4 and 5 arranged asa branch circuit to the conduit 6 of the pumping machine which provideseither a pressure or a vac uum. This conduit 6 is closed at itsextremity 7, the closed extremities 2 and 7 of the tube and the conduitbeing located on the same side with respect to the pipes 4 and 5. Theoperation would be identically the same if the conduit were closed atits upper extremity and connected to the pumping machine by its lowerextremity.

Each pipe 4 (or 5) is provided with a floating clapper-valve 8 (or 11)constituted by a light disc of plastic material, leather, rubber or anyother appropriate material, floating freely in a guiding cape 10 (or 13)in which is provided a second fixed disc 9 (or 12), pierced with acentral opening, the periphery of which serves as a seating for thefloating valve. When the direction of flow of the air tends to lift thevalve from its seat, the flow of air circulates freely. On the otherhand, the clapper stops the flow of air when the latter applies thefloating valve against its seat. The complete device necessitates twofloating clapper-valves mounted in opposition, as shown in FIG. 1.

All the advantage of the floating clapperwalves resides in the fact thatthey are simple devices which operate automatically by the sole effectof the flow of air utilized for the conveyance of the carriers.

The operation of this device is the same whether the pumping machine isworking in suction or in delivery.

The effectiveness of the automatic braking of the carriers increases inproportion with the distance which separates the two pipes 4 and 5 fromeach other. In practice however, this distance is limited by the layoutconditions of the pneumatic circuit, to about two or three times thelength of a carrier.

FIG. 2 shows a pneumatic installation according to the invention withtwo despatching-receiving stations 14 and 15, each equipped with thebraking device shown in FIG. 1. The installation also comprises twosuction machines 16 and 17 respectively associated with the stations 14and 15, and the travel of the carriers between the two stations iseffected in a single conveyor tube 1, in one direction or the other. Thetwo floating clapper-valves with which each of the two stations isprovided are indicated diagrammatically, the arrow showing in each casethe direction of travel of the air when the floating clapper-valve isopen.

The operation of such an installation is as follows:

When a despatch is effected from the station 14, the propulsion of thecarriers is then ensured by the suction machine 17 located at the otherend station 15 of the pneumatic tube. The suction of this machine closesthe downstream floating clapper-valve 40 and opens the upstream floatingclapper-valve 41 with respect to the direction of travel of thecarrierof the despatching station.

The despatcher manually opens the shutter which closes the extremity ofthe pneumatic tube and introduces a carrier which is caught-up in thesuction flow along the upstream pipe system and is sucked towards theother station. The despatcher re-closes the shutter which automaticallylocks itself.

When a reception is effected at the station 15, the vacuum is created bythe suction machine 17 close to the station of destination. When thismachine is in operation, the upstream floating clapper-valve 42 isopened and the downstream floating clapper-valve 43 with respec to thedirection of travel of the carrier closes. The flo w oi eonveying air inthe pneumatic tube follows the upstream piping system and the pneumatictube element comprised between the two floating clapper-valves is aclosed space in which the carrier compresses the air and is thuseffectively slowed down.

It is quite clear that the installation shown in FIG. 2 may also operateunder pressure, if the machines 16 and 17 working on suction arereplaced by machines 16 and 17 working on compression. In this case,there is the same quality of braking of the carriers on their arrival,the only difference being that during a despatch, it is the machineadjacent to the despatching station which is actuated, while for areception the pressure is provided by the machine at the other station.

Such an installation permits of a displacement of carriers in a simpleto-and-fro movement in a single pneumatic tube between two stations.

If it is desired to effect communications in a double to-and-fro systemfrom a given station, that is to say communications with two otherstations by a single tube in one direction or the other, there may beemployed an installation such as shown in FIG. 3.

In order to connect the station 18 in a shuttle service to two otherstations 19 and 20 according to the invention, it is economical toeffect the operation of both the two connections with two machines 21and 22 only (and not four) installed in the vicinity of the end stations19 and 20. This assumes, of course, that the whole of the two distancesbetween the stations is relatively moderate and is compatible with thepower of the machines provided for ensuring the transport of thecarriers.

In this case, the floating clapper-valves continue to play their part inthe braking of the arrival of the pneumatic carriers, whether thepneumatic tube is working under vacuum or under pressure.

The end stations 19 and 20 each comprise, without any modifications, thedevice indicated for one of the stations shown in FIG. 2 and a machineworking under vacuum or under pressure.

With regard to the central station 18 at which the two shuttle servicesterminate, this is equipped with a set of two floating clapper-valvesconnected to the points of despatch and reception of each of the twolines, as indicated in FIG. 3. The operation of the variousclappervalves during a despatch or a reception, either under vacuum orunder pressure, is similar to that of the installation of FIG. 2.

There has been shown in FIG. 4 a further pneumatic installation whichmakes use of the floating valve device according to the invention.

Pneumatic installations are already known which comprise a mainpneumatic tube 33 on which are mounted pneumatic branch tubes connectedto the main tube by air-tight switching points 28, 29 and 30. By virtueof a pumping system 23 capable of operating alternatively under vacuumor under pressure and located for example at one of the extremities ofthe line, as shown in FIG. 4, the installation permitsintercommunication between a number of pneumatic stations 24, 25, 26 and27, in one direction or in the other, with a single pneumatic conveyortube.

In an installation of this kind, a carrier despatched from any one ofthe stations 24, 25, 26 or 27 is first of all sucked into the main tube33 and is then delivered under pressure through a portion of the maintube and the branch tube corresponding to the station of destination.

In order that the carrier may obey this reversal of condition, whichpasses from suction to delivery, its travel under vacuum must bestopped. To this end, it is possible:

either to stop its movement before the pumping machine against a fixedabutment in the interior of the tube, in which case the carrier becomesrapidly deteriorated by severe and repeated shocks;

or to arrange between the end station 24 and the pumping machine 23, apneumatic tube element having a length of at least 10 metres, in whichthe carrier loses its speed by inertia, this however being practicallyimpossible to achieve in the majority of installations.

In order to avoid these disadvantages, it is possible to effect theconnection according to the invention between the conduit 36 of thepumping system, one of the extremities 37 of which is closed, and anelement 34 of the main pneumatic tube 33, closed at one of itsextremities 35, by the addition to each extremity of this element, of apiping system provided with a floating clapper-valve, the two valves 31and 32 being mounted in opposition and in such manner as to permit'thearrival of air at the closed extremity of the element.

During operation under vacuum, the floating valve 31 is closed and thefloating valve 32 is open. The carrier arriving in the element 34, whichis closed, is stopped rapidly and without any shock.

A device of this kind is also applicable if the stations are providedwith an automatic carrier despatching system. In the case of theinstallations shown in FIGS. 2 and 3, the admission of outside air intothe main pneumatic tube in the case of operation under vacuum, or itsevacuation in the case of operation under pressure, is effected throughthe opposite machine which is assurned to be of the centrifugal type. Acentrifugal machine when stopped has in fact a large clearance betweenthe turbine and the body which readily permits the passage of air andonly creates a negligible loss of pressure. 7 i

This is not the case when the great length of the pneumatic tube is thecause of a large drop in pressure which a centrifugal machine cannotovercome. It is then necessary to employ a volumetric machine capable ofsupplying a vacuum (or a pressure) three or four times higher than thatof a centrifugal machine. However, a volumetric machine is formed by arotary system which is closely fitted into the interior of the body ofthe machine, and which does not permit the passage of the air to beadmitted into the pneumatic tube when the machine is stopped.

It is therefore necessary to add to the volumetric machines of apneumatic tube serving for the conveyance of carriers in one directionor in the other, an automatic air-inlet device.

This-automatic device may be either an electrical or pneumatic valve,the overall size and weight of which result in additional cost ofinstallation and in which especially the cost is high when the diameterof the line tube is large, or a double floating clapper-valve.

When a pneumatic installation comprises a volumet- -ric machine, thedevice for slowing down the carriers in a pneumatic tube element closedat one of its extremities, comprises according to the invention a pipingsystem connecting together the two extremities of this element andprovided with a floating clapper-valve having a double seating and avolumetric pump con nected in series, this valve being interposedbetween the machine and the closed extremity of the element.

An installation of this type is shown in FIG. 5. The station 39 providesfor the despatch or reception of pneumatic carriers travelling inside apneumatic tube 38 which terminates in an element 40, the extremity 41 ofwhich is closed by a shutter. A piping system 42 located at thenon-closed extremity of the element 40, passes successively through avolumetric machine 45 and a floating clapper-valve 44 with a doubleseating, before terminating in a pipe 43 at the closed extremity of theelement 40.

The floating valve 44 with a double seating is constituted by a lightdisc as described above, floating freely between two fixed discs 46 and47 pierced with a central hole in the interior of a guide-cageinterposed between the station 39 and the volumetric machine 45.

The piping 42 is connected to the pneumatic tube at a distance from thestation equal to about two or three times the length of a pneumaticcarrier.

The operation of this installation is as follows: When a despatch iseffected and the installation is designed to operate under vacuum forexample, the vacuum is created by the pump at the other station. Thefloating clapper-valve 44 with a double seating, which normally rests onits lower seating 47, leaves free the orifice of the upper seating 46through which the outside air is admitted into the pneumatic tubeelement 40 through the intermediary of the piping 43. As soon as it isintroduced into the vicinity of the closed extremity of the element 40,the carrier is sucked along by the flow of air which propels it towardsthe other station.

When a reception is effected, which will also be assumed to be in avacuum system, it is the volumetric machine 45 in the vicinity of thereceiving station which is started-up, and air is admitted to thepneumatic tube 38 at its other extremity, not shown in FIG.

5. The delivery pressure of the machine 45 lifts the floatingclapper-valve 44 which, simultaneously acted upon from below by apressure and from above by the vacuum existing in the pneumatic tube,closes the orifree of the upper seating 46 and opens that of the lowerseating 47 through which the exhaust of the machine 45 flows. At itsarrival, the carrier passes into the closed tube element 40 and istherefore braked by compressing the air in the tube in front of it.

It will be noted that an installation of this kind can also operateunder pressure in one direction or in the other.

In addition to its simplicity and its low production cost, thisinstallation has a further very important advantage which is as follows:

When a pneumatic tube, acting in one direction or the other, connectstogether two distant buildings, following a path in which there exists asubstantially uniform temperature, the external air is admitted into thetube at the floating clapper-valve with a double seating.

On the other hand, if this pneumatic tube passes into cold rooms,(attics, empty sanitary spaces, external gutters for example), thepropulsion of the pneumatic carriers is liable to be hindered by theproduction of condensed water inside the tube. It is then essential tointroduce into the tube only air which has a sufficiently lowtemperature so that there cannot rise any condensation during the courseof its passage through the coldest places. This air must therefore betaken from a room at low temperature if such exists in proximity to thetube or the air must be condensed in a refrigerator.

For this purpose, the floating clapper-valve 44 may be enclosed in afluid-tight casing 49 which is connected by a conduit 48 to a cold roomor a refrigerator, as shown in dotted lines in FIG. 5.

The floating clapper-valve with a double seating thus replaces a set ofvalves with electrical or pneumatic operation which are very expensive.This replacement is very advantageous, since this system is simpler andits automatic operation is more reliable because it only makes use ofthe flow of air utilized for the propulsion of the pneumatic carriers.

I claim:

1. An installation for conveying carriers by a pneumatic tube,comprising a pneumatic tube in which the displacement of the carriers iseffected in one direction or in the other, a volumetric pumping machinefacilitating the reversal direction of the flow of air serving to propelcarriers inside the tube, and at least one station permitting thedespatching and reception of said carriers, said installation beingcharacterized in that the said pneumatic tube comprises a closedextremity terminating in a station with two piping systems coupled toeach other through the intermediary of a floating clappen valve with adouble seating and said volumetric pumping machine connected in series,said clapper-valve being interposed between said machine and the pipingwhich is closest to the closed extremity of the pneumatic tube.

2. An installation in accordance with claim 1, characterized in that thesaid floating clapper-valve with double seating is enclosed in a fluidtight casing which communicates with a source of refrigerated air at atemperature lower than the temperatures existing in the various parts ofthe installation.

1. An installation for conveying carriers by a pneumatic tube,comprising a pneumatic tube in which the displacement of the carriers iseffected in one direction or in the other, a volumetric pumping machinefacilitating the reversal direction of the flow of air serving to propelcarriers inside the tube, and at least one station permitting thedespatching and reception of said carriers, said installation beingcharacterized in that the said pneumatic tube comprises a closedextremity terminating in a station with two piping systems coupled toeach other through the intermediary of a floating clapper-valve with adouble seating and said volumetric pumping machine connected in series,said clapper-valve being interposed between said machine and the pipingwhich is closest to the closed extremity of the pneumatic tube.
 2. Aninstallation in accordance with claim 1, characterized in that the saidfloating clapper-valve with double seating is enclosed in a fluid tightcasing which communicates with a source of refrigerated air at atemperature lower than the temperatures existing in the various parts ofthe installation.